Liquid crystal panels have been used as display parts in display devices such as smartphones and tablet computers. Such a liquid crystal panels does not emit light by itself and therefore, uses light from the lighting device (a backlight device). Such a lighting device is arranged on a rear-surface side of the liquid crystal panel and configured to emit planar light spreading over a rear surface of the liquid crystal panel.
An example of the lighting device includes a light guide plate and a light source of light emitting diodes (LEDs) that are arranged opposite an edge surface of the light guide plate. Such a lighting device is a lighting device of an edge light type (or a side light type) and is preferably used to reduce a thickness of the device and consumption of power.
In such an edge-light type lighting device, the edge surface of the light guide plate is a light entrance surface through which light emitted by the LED light source enters the light guide plate and a front-side plate surface of the light guide plate is a light exit surface through which the light entering through the light entrance surface travels exits the light guide panel toward the liquid crystal panel. Light entering the light guide plate through the light entrance surface travels within the light guide plate with being reflected repeatedly and exits the light guide plate through the light exit surface.
According to increased variation of design and usages of display devices, the liquid crystal panel may include a non-display area in the display area and no image is displayed in the non-display area. For example, in the configuration of Patent Document 1, a window portion of a hole is formed through the liquid crystal panel and the lighting device as the non-display area within the display area. Such a window portion is formed to check a rear-surface side of the display device from the front surface (display surface) side.
In the display device including the edge-light type lighting device, a through hole corresponding to the non-display area is formed in the light guide plate of the lighting device to provide the non-display area within the display area of the liquid crystal panel.